1. Field of the Invention
The present invention relates to a color solid state image pick-up device and a combination of color filters for obtaining the color picture signal making use of color image pick-up elements.
2. Description of the Prior Art
As color solid state image pick-up devices, one, two or three imagers of charge carrying image pick-up elements (hereinafter called CCD) are used, and a single imager type camera, a double imager type camera and a triple imager type camera can be thought therefore. However, the present invention particularly relates to the single imager image pick-up device in which one CCD is used.
In the case of the conventional single imager type solid state image pick-up devices in which solid image pick-up elements such as CCD are used, the color filter array is superposed on each image pick-up cell of the image pick-up elements one to one so as to separate the color signals. In the color filter array used in such a single imager type solid state image pick-up device, the red, the green and the blue filter elements are arranged in the shape of mosaic in order to economize the number of the image pick-up cells in CCD. Generally color filters called Bayer arrangement is used.
When the color filters arranged in the shape of mosaic are combined into CCD of the frame transfer type so as to constitute a single imager type color camera, a considerable leakage of signals takes place between the adjacent cells due to its construction, and the colors are mixed, which leads to an insufficient color separation.
Although a method for overcoming the above difficulty has already been proposed by the present inventors (Jap. Pat. Pub. No. Sho 56-115085) and the problem has been largely resolved, the vertical image resolution power is low because the effective range of the sensitivity along the vertical direction is large, while the pseudo-color signals or the contour take place in the image not having a vertical correlation in which the bright and the dark part exist on both sides of a line parallel to the color filter array, so as to lower the quality of the image because it is hereby presumed that a correlation exists along the vertical direction.